This project is a pilot safety and immunogenicity study of transcutaneous vaccination with live attenuated Listeria monocytogenes BMB72 bacteria (actA/plcB-deleted, expressing influenza A nucleoprotein) and a cutaneous adjuvant, native purified cholera toxin. Transcutaneous vaccination is needle-less application of materials directly to the skin. Healthy adult volunteers (4 per group) will receive either: